Shares in Paddy Power Betfair, which completed the merger in February, slid 2.6pc to £96.90 after it reported a first-half operating loss of £47.5m on a proforma basis, compared with a £106.5m profit a year earlier. On a statutory pre-tax basis, the loss was £45.9m.

The betting company’s results were knocked by £195m in one-off costs linked to the blockbuster tie-up, including £29m in advisory fees “which my investment banker friends tell me is on the low end of the range”, said boss Breon Corcoran.

The loss overshadowed the news that Paddy Power Betfair had hiked the synergies it now expected from the merger, forecasting £65m in annualised cost savings by next year, compared with the £50m per annum it had estimated from 2018.

“People have been really diligent, there’s been an awful lot of hard work done, and promptly,” said Mr Corcoran of efforts to combine the two companies.

The merger of Paddy Power and Betfair to create an £8bn company is regarded as one of the canniest of a series of deals that has swept Britain’s gambling industry in the past year. Online gaming firm GVC bought rival Bwin.Party and bookies Ladbrokes and Coral are also in the midst of a merger, which will see them offload about 400 shops to ease competition concerns.

Paddy Power Betfair has “been involved” in the process of buying some of the Ladbrokes and Coral shops, which is ongoing, and has been eyeing a “smaller number” of sites, Mr Corcoran said.

England crashed out to Iceland in Euro 2016, providing a fillip for Paddy Power Betfair

“If the right asset came up at the right price, then we’d be very well positioned to do that, but we have our hands full at the minute with integration,” he said.

Paddy Power Betfair’s revenues for the six months to the end of June rose 18pc to £759m, boosted by the European Championship football tournament this summer that generated £38m for the company. England, who were knocked out by minnows Iceland, did not make it to the quarter finals. But England’s loss was Paddy Power Betfair’s gain.

“I hate dwelling on it but England’s underperformance helped, Portugal had quite a number of draws, which helped,” said Mr Corcoran. “The Olympics, on the other hand, was a fascinating spectacle to watch but very little interest in the betting other than a couple of events like the 100m sprint.”

Separately, the company announced that Stewart Kenny, one of the co-founders of Paddy Power 28 years ago and its first chief executive, was stepping down as a non-executive. Mr Kenny’s retirement marks the end of four decades in the betting industry.

Meanwhile betting company Sportech enjoyed a 4pc rise in adjusted first-half pre-tax profits to £5.6m and said talks to sell its 93-year-old Football Pools business were continuing. The Liverpool-based company has never revealed the identity of the suitors for the division. However, it emerged in February that Sportech’s former chief operating officer, Ian Hogg, was eyeing a deal for the business.